Nickel-Iron batteries have 10-20 times less energy density and are more difficult to manufacture. You might get a battery that lasts 30-50 years instead of 5-10

Nickel-Iron batteries have 10-20 times less energy density and are more difficult to manufacture. You might get a battery that lasts 30-50 years instead of 5-10 years but at a cost increase that's greater than the gain in number of cycles.